[Python-checkins] cpython: Revert change 0eb8c182131e:
victor.stinner
python-checkins at python.org
Tue Sep 8 23:59:20 CEST 2015
https://hg.python.org/cpython/rev/d0bb896f9b14
changeset: 97781:d0bb896f9b14
user: Victor Stinner <victor.stinner at gmail.com>
date: Tue Sep 08 23:58:54 2015 +0200
summary:
Revert change 0eb8c182131e:
"""Issue #23517: datetime.timedelta constructor now rounds microseconds to
nearest with ties going away from zero (ROUND_HALF_UP), as Python 2 and Python
older than 3.3, instead of rounding to nearest with ties going to nearest even
integer (ROUND_HALF_EVEN)."""
datetime.timedelta uses rounding mode ROUND_HALF_EVEN again.
files:
Lib/datetime.py | 4 ++--
Lib/test/datetimetester.py | 18 ++++++++++++------
Misc/NEWS | 7 +------
Modules/_datetimemodule.c | 22 +++++++++++++++++++++-
4 files changed, 36 insertions(+), 15 deletions(-)
diff --git a/Lib/datetime.py b/Lib/datetime.py
--- a/Lib/datetime.py
+++ b/Lib/datetime.py
@@ -407,7 +407,7 @@
# secondsfrac isn't referenced again
if isinstance(microseconds, float):
- microseconds = _round_half_up(microseconds + usdouble)
+ microseconds = round(microseconds + usdouble)
seconds, microseconds = divmod(microseconds, 1000000)
days, seconds = divmod(seconds, 24*3600)
d += days
@@ -418,7 +418,7 @@
days, seconds = divmod(seconds, 24*3600)
d += days
s += seconds
- microseconds = _round_half_up(microseconds + usdouble)
+ microseconds = round(microseconds + usdouble)
assert isinstance(s, int)
assert isinstance(microseconds, int)
assert abs(s) <= 3 * 24 * 3600
diff --git a/Lib/test/datetimetester.py b/Lib/test/datetimetester.py
--- a/Lib/test/datetimetester.py
+++ b/Lib/test/datetimetester.py
@@ -663,14 +663,16 @@
# Single-field rounding.
eq(td(milliseconds=0.4/1000), td(0)) # rounds to 0
eq(td(milliseconds=-0.4/1000), td(0)) # rounds to 0
- eq(td(milliseconds=0.5/1000), td(microseconds=1))
- eq(td(milliseconds=-0.5/1000), td(microseconds=-1))
+ eq(td(milliseconds=0.5/1000), td(microseconds=0))
+ eq(td(milliseconds=-0.5/1000), td(microseconds=-0))
eq(td(milliseconds=0.6/1000), td(microseconds=1))
eq(td(milliseconds=-0.6/1000), td(microseconds=-1))
- eq(td(seconds=0.5/10**6), td(microseconds=1))
- eq(td(seconds=-0.5/10**6), td(microseconds=-1))
- eq(td(seconds=1/2**7), td(microseconds=7813))
- eq(td(seconds=-1/2**7), td(microseconds=-7813))
+ eq(td(milliseconds=1.5/1000), td(microseconds=2))
+ eq(td(milliseconds=-1.5/1000), td(microseconds=-2))
+ eq(td(seconds=0.5/10**6), td(microseconds=0))
+ eq(td(seconds=-0.5/10**6), td(microseconds=-0))
+ eq(td(seconds=1/2**7), td(microseconds=7812))
+ eq(td(seconds=-1/2**7), td(microseconds=-7812))
# Rounding due to contributions from more than one field.
us_per_hour = 3600e6
@@ -683,6 +685,10 @@
eq(td(hours=-.2/us_per_hour), td(0))
eq(td(days=-.4/us_per_day, hours=-.2/us_per_hour), td(microseconds=-1))
+ # Test for a patch in Issue 8860
+ eq(td(microseconds=0.5), 0.5*td(microseconds=1.0))
+ eq(td(microseconds=0.5)//td.resolution, 0.5*td.resolution//td.resolution)
+
def test_massive_normalization(self):
td = timedelta(microseconds=-1)
self.assertEqual((td.days, td.seconds, td.microseconds),
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -17,18 +17,13 @@
Library
-------
-- Issue #22241: timezone.utc name is now plain 'UTC', not 'UTC-00:00'.
+- Issue #22241: timezone.utc name is now plain 'UTC', not 'UTC-00:00'.
- Issue #23517: fromtimestamp() and utcfromtimestamp() methods of
datetime.datetime now round microseconds to nearest with ties going away from
zero (ROUND_HALF_UP), as Python 2 and Python older than 3.3, instead of
rounding towards -Infinity (ROUND_FLOOR).
-- Issue #23517: datetime.timedelta constructor now rounds microseconds to
- nearest with ties going away from zero (ROUND_HALF_UP), as Python 2 and
- Python older than 3.3, instead of rounding to nearest with ties going to
- nearest even integer (ROUND_HALF_EVEN).
-
- Issue #23552: Timeit now warns when there is substantial (4x) variance
between best and worst times. Patch from Serhiy Storchaka.
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -2149,9 +2149,29 @@
if (leftover_us) {
/* Round to nearest whole # of us, and add into x. */
double whole_us = round(leftover_us);
+ int x_is_odd;
PyObject *temp;
- whole_us = _PyTime_RoundHalfUp(leftover_us);
+ whole_us = round(leftover_us);
+ if (fabs(whole_us - leftover_us) == 0.5) {
+ /* We're exactly halfway between two integers. In order
+ * to do round-half-to-even, we must determine whether x
+ * is odd. Note that x is odd when it's last bit is 1. The
+ * code below uses bitwise and operation to check the last
+ * bit. */
+ temp = PyNumber_And(x, one); /* temp <- x & 1 */
+ if (temp == NULL) {
+ Py_DECREF(x);
+ goto Done;
+ }
+ x_is_odd = PyObject_IsTrue(temp);
+ Py_DECREF(temp);
+ if (x_is_odd == -1) {
+ Py_DECREF(x);
+ goto Done;
+ }
+ whole_us = 2.0 * round((leftover_us + x_is_odd) * 0.5) - x_is_odd;
+ }
temp = PyLong_FromLong((long)whole_us);
--
Repository URL: https://hg.python.org/cpython
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